Winter Worm Control For horses tapeworm testing Spring/Autumn

Winter worm control

For horses tapeworm testing Spring/Autumn

The winter protocol varies slightly compared to the other seasons as it’s the time of year when we need to consider encysted redworm in our programme, the potentially dangerous larval stage of the small redworm.


Your Winter Parasite Control

1. TEST: Take a worm egg count in the usual way. Await the results. 

2. TREAT: Treat with the appropriate winter worming product. 

3. TEST AGAIN: If the first worm egg count was positive (200 e.p.g. or above) then we will send a separate worm egg count to you to be used as a reduction test, 10-14 days after treatment. This will monitor whether any resistance is present to the chemical that was used. If the first worm egg count came back as <50 e.p.g. then there’s no need to carry out a reduction test.

This information is for Complete Care subscribers that have elected to test their horses for tapeworm in the Spring and Autumn and need to know what their winter parasite control programme will be. There are a number of things to take into consideration for each individual horse; we know that it's tempting to want a date in the calendar but in practice parasites don't have diaries and we need to consider factors such as environment, ground temperatures, if your horse may qualify for the small redworm blood test and also your horse's overall parasite control programme.

📮 We’ll send a worm egg count to carry out for your horse at the appropriate time. This will give us useful information but it can’t detect encysted stages of the small redworm. For this reason you will also need to either treat proactively with a suitable wormer or blood test with your vet.  If you’re treating we’ll also use this season to carry out a reduction test to measure the effectiveness of the chemical, also enclosed.

When to address encysted redworm?

❄️ We usually aim for the months between December and February, approx 8-12 weeks after your last worm egg count and at a time when daytime temperatures have regularly dropped below 6 degrees. This helps to reduce parasite activity on the pasture.

What to treat with?

Moxidectin (Equest) is the preferred treatment for encysted redworm, particularly if targeting bots at the same time for most equines. As you considered tapeworm in the autumn the moxidectin + praziquantel is not required unless specifically advised. There are circumstances where a 5 day course of fenbendazole (Panacur Equine Guard) is more appropriate - where moxidectin is contra-indicated and for youngstock who are also susceptible to roundworm infection.

Horses on our high risk programme will worm count twice in the winter – in exceptional circumstances a second treatment for encysted redworm may be required.

The Small Redworm Blood Test

If your horse is classed as low risk, has had worm egg counts consistently below <200epg over the last year, is in a closed herd with good paddock management and there is frequent poo picking, then they may be a candidate for the encysted redworm blood test. This innovative test detects encysted as well as adult stages of the small redworm and gives a recommendation as to whether treatment is advised or not. Of course it is an additional cost but every horse that does not require a moxidectin dose is helping preserve this key medicine and delay resistance.


⚠️ Moxidectin shouldn’t be given to underweight horses, foals under 4 months old (6.5 months if also combined with praziquantel) and isn’t licenced for donkeys.

We also advise caution if using it in miniature Shetlands unless you can calculate dosage accurately. This is because the active ingredient is stored in body fat and these animals don’t have sufficient stores to take up the drug.